1. Field of the Invention
The present invention is generally directed to a communication system, and more particularly to managing the power utilized by a buffered packet switching network component of a communication system.
2. Background Information
Various bandwidth control mechanisms have been utilized for congestion avoidance in communications systems that include buffered packet switching network components. For example, a number of random early detection (RED) algorithms have been implemented in terrestrial-based gateways. A typical gateway, implementing a RED algorithm, notifies packet sources and packet destinations of congestion either by dropping packets or by setting a bit in a header of a given packet. In this manner, a RED gateway attempts to keep its average queue size low while storing occasional bursts of packets in its queue.
Various forms of RED algorithms have been implemented within gateways. Examples of known RED algorithms include weighted RED, adaptive RED, distributed RED, distributed weighted RED, etc. Such algorithms implementing the assorted forms of RED are well known to one of ordinary skill in the art. RED algorithms have also been implemented in packet-based network components that include buffers (e.g., FIFO buffers) other than gateways (e.g., routers). As mentioned above, the purpose of RED is to prevent buffer overflow while maintaining a near maximum utilization of the packet network. A given RED algorithm generally performs a time-weighted average buffer size calculation that is compared to a set of marking and/or deleting parameters. If the average buffer size falls below the minimum parameters, no action is taken. If the average buffer size exceeds the maximum parameters, an action, such as marking or deleting, is guaranteed to occur. When the average buffer size falls between the minimum and maximum parameters, the probability that an action (marking or deleting) will occur is a function, e.g., linear proportion, of the average buffer size.
An adaptive RED implementation monitors how long the average buffer size is in each of three distinct domains (i.e., less than a minimum, between the minimum and a maximum, and greater than the maximum) and adjusts the minimum and maximum parameters for marking and deleting, accordingly. Reducing either marking parameter increases the probability that a packet is marked, thus signaling congestion to the packet destination. In response to receiving a marked packet, a packet destination typically sends a request to the packet source to reduce the rate at which packets are sent through the congested link. In this manner, the various forms of RED attempt to enlist the aid of network users to voluntarily reduce traffic, so as to prevent buffer overflow and the subsequent loss of packets. RED algorithms have also been implemented in various space-based packet switching network components (e.g., satellites) in an effort to reduce component congestion.
In addition to congestion in a packet switching network component, another matter of concern with respect to satellites and many other devices that include packet switching network components, is power management. A typical satellite includes storage cells or batteries that supply operating power to the electronic circuits of the satellite. These storage cells or batteries, which are recharged by solar panels, store energy for use during high power demands or during dark periods. Dark periods occur when a given satellite, within a constellation, is shadowed from the Sun by the Earth. At most, a typical satellite, within a constellation, may be shadowed by the Earth for thirty-five percent of its orbit. At best, each individual satellite is typically in full view of the sun for approximately thirty percent of its orbit. Thus, during high power demands or dark periods, satellite power management is typically necessary. Additionally, terrestrial-based packet switching network components can benefit from power management (i.e., conservation) during peak power usage, among other conditions.